No flow in radiant heat loops?

[Oe478]

Hey everybody new here 1st post but have gotten lots of good info from site,anyway i have a radiant system in my garage which is t26x40 with 12' ceilings & r19 in walls & ceilings,the system is 4 loops of 1/2" pex app. 300'long with a 11kw titan tankless water heater for heat with rifeng manifolds,spiro air eliminator, taco 009 pump,&a radiant 12lb. Expansion tank. It does work but the flow meters show 0 flow & the return temp is 35-40 degrees cooler than supply so im thinking that theres obviously some flow through loops , have purged air twice btw,and mo change to flow meters.just kinda stumped at this point.

 

[anthony666]

more pictures

 

[HummerJack7]

Turn the water supply on from the blue pex and then open the green water hose into a bucket while the circulating pumps are on. If it spits, you have air. When it runs a steady stream most of the air will be out. You will still have to bleed the expansion tank bleeder. *Make sure there is at least 12-15psi in the tank.

http://www.masterplumber.net/expansion_tank.htm

If the the pressure return flow is still low it cold be ice in the line or an an air lock further down the line. You could test each circuit loop by turning them all off and then turn one on and record the flow rate. Then repeat for all four loops.

 

[BD1]

Need pics of manifold piping and additional info. Is the system straight water ? Glycol ? Is there shutoff valves on each circuit ? Purge valve on header manifold ? There are many postings about radiant systems. Type in radiant.
http://www.garagejournal.com/forum/search.php?searchid=14054351

 

[Oe478]

I posted more pics but they didnt come up for dome reason, ill try again. Right now its just straight water in it, it hasnt been real cold here & its 50 in the garage so pretty sure its not ice.thanks for quick replys.

 

[Oe478]

Trying to post more pics.

 

[anthony666]

is that regular plumbing pex or oxygen barrier heating pex ??

 

[Oe478]

Sorry for all the posts but i can only post 1 pic at a time for some reason.

 

[Oe478]

The blue is just regular pex but the loops are oxygen barrier pex.

 

[anthony666]

i'm talking about the white pex that feeds the manifolds

 

[Oe478]

Oh,i forgot about that white pex, yes its only regular plumbing pex.

 

[anthony666]

change it

 

[Oe478]

Ok , ill give it a shot,do u think its sucking air through it?

 

[Champ49]

I have the same manifold, with no instructions, and it took a while to figure out the red rings lift up to allow adjustment of the flow. They came pretty much closed.

 

[anthony666]

no, i think it probably needs a good high pressure purge .. the plumbing pex will bite you in the *** later when your pumps seize and the boiler rots out

 

[Oe478]

Ya,the instructions arnt great to say the least,the only way i can even get the meters to show any flow is to totally shut off 2 loops then the other 2 will show about .25gpm, otherwise theyre all about half full with water but the little red plungers dont register any flow.and yes iguess another purge couldnt hurt either.

 

[Spire]

I have those same manifolds and found that the little red plastic thing in the flow meters have a casting burr (for lack of a better term) that causes them to stick.

You will have flow, but the red guy will not lift accurately.

Unscrew the flow meter part (its pressure containing, block in the manifold first), pull them apart and cut or sand the burr off and they will move much more accurately.

 

[Oe478]

Oh, i guess i could try that too,never really thought about taking those apart but at this point i dont have anything to lose,i guess thats what u get for $139.99 these days.

 

[atotalnincompoop]

i have a similar manifold, my flowmeters dont show anything, the little red discs are just stuck at the top of each one. mine didn't have any instructions regarding adjustment, i email the vendor and ,go figure, got no response

 

[Spire]

i have a similar manifold, my flowmeters dont show anything, the little red discs are just stuck at the top of each one.

Trim the small burr off the red things, that's whats holding them in the up position.

 

[atotalnincompoop]

Trim the small burr off the red things, that's whats holding them in the up position.

i finally got all the air out of my system , i'd hate to open it up and have to start all over

 

[Oe478]

I took flow meters out , they seem to move freely, didnt really see a burr on them, maybe theyre just junk& dont work.

 

[HiItsMeJimmy]

I have the same manifold! Had them cranked all the way in clockwise for 3 days... had no flow in any loops. Cranked them all the way out counterclockwise and gauges began to read.

 

[The_Hun]

Don't forget that a lot of these manifolds also have flow adjusters on the cold return side of each loop on the manifold.. Make sure those aren't all shut too..

 

[Dick in Wisconsin]

Who is the manufacturer of the Manifold? I'd like to stay away from it and them.

 

[Oe478]

Rifeng makes the manifold

 

[atotalnincompoop]

mine is a gtflow from pex direct on ebay. not good!!